Erysiphe 229 



Tanacctuni vulgarc, TjpJia latifolia {s),UImus alata, U. Americana, 

 U.caiiipcstris, U. montaua^ Vaccbdinn stamincum^ litis Ladrusca 

 (36), XantJioxyluin A))i€ricamiui, 



Distribution, — Europe: Britain. France, Portugal (396), Bel- 

 ■ gium, Netherlands, Germany, Switzerland, Italy, Austria-Hungary, 

 Denmark, Norway, Sweden, Finland, Russia. 

 Africa : Alereria. 



Asia: Turkey (Aleppo), Transcaucasia {ll^^y Siberia (IMinus- 

 sinsk) (235), China (Yun-nan) (273), Japan. 



South America: Paraguay (335), Patagonia {n^), Tierra 

 del Fuego (337). 



Central America : Guatemala. 



North America : Mexico ; United States — New Hamp- 

 shire, Massachusetts, Connecticut, New York, Pennsylvania, West 

 Virginia, South Carolina, Ohio, Michigan, Indiana, Alabama, Illi- 

 nois, Mississippi, Wisconsin, Missouri, Iowa, Minnesota (325), 

 South Dakota (151), Kansas (386), Montana, Wyoming, Cali- 

 fornia, Washington ; Canada — ^Ontario, Newfoundland. 



Phyllactinia coryica is the most sharply characterized and one 

 of the most widely spread species of the Erysiphaceae. The large 

 size of the perithecium, and the acicular appendages with a bulbous 

 base, enable the present species to be easily recognized, usually 

 with the naked eye. 



Nevertheless, as will be s^^vl from the synonomy, P, coryica 

 has had many names given to it This has been due partly to the 

 fact that the appendages are either very fragile or deciduous, and 

 so the fungus under different conditions has been supposed to 

 belong to different species ; for the most part, however, these 

 names owe their origin to the fact that P, corvlca grows on a very 

 large number of hosts, and in former times the occurrence of a 

 species of mildew on a n^w host-plant usually led to the descrip- 

 tion of the fungus as a new species. 



There can be no doubt, when sufficient material is examined, 

 that only a single species of Phyllactinia exists. Whether on its 

 numerous hosts in America (w^here Burrill states that *' scarcely a 

 deciduous-leafed tree seems proof against it "), whether on Par- 

 mcnticra alata in Guatemala, Erythrina in IMexico, on Morns alba 

 and Pauloivnia impcrialis in Japan, or on the Cupuliferae of Europe, 



